A 99 minute Double-lined White Dwarf Binary from SDSS-V

Abstract

We report the discovery of SDSS J133725.26+395237.7 (hereafter SDSS J1337+3952), a double-lined white dwarf (WD+WD) binary identified in early data from the fifth-generation Sloan Digital Sky Survey (SDSS-V). The double-lined nature of the system enables us to fully determine its orbital and stellar parameters with follow-up Gemini spectroscopy and Swift UVOT ultraviolet fluxes. The system is nearby (d = 113 pc), and consists of a 0.51 M ⊙ primary and a 0.32 M ⊙ secondary. SDSS J1337+3952 is a powerful source of gravitational waves in the millihertz regime, and will be detectable by future space-based interferometers. Due to this gravitational wave emission, the binary orbit will shrink down to the point of interaction in ≈220 Myr. The inferred stellar masses indicate that SDSS J1337+3952 will likely not explode as a Type Ia supernova (SN Ia). Instead, the system will probably merge and evolve into a rapidly rotating helium star and could produce an underluminous thermonuclear supernova along the way. The continuing search for similar systems in SDSS-V will grow the statistical sample of double-degenerate binaries across parameter space, constraining models of binary evolution and SNe Ia.

Observationally driven Galactic double white dwarf population for LISA

“…This has changed with the second data release of the Gaia mission (Gaia Collaboration 2016, 2018, which has revealed, for the first time, the nearby Galactic WD population in the least biased form so far (Gentile Fusillo et al 2019 ). The fifth generation of the SDSS (SDSS-V; Kollmeier et al 2017 ), which has already started collecting data in 2020 (with a first DWD was already published by Chandra et al 2021 ), will acquire multi-epoch spectra for a large fraction of the Gaia WDs, revealing the properties of the Galactic WD population clearer than ever before. In the nearer future, the follow-up study of the DWD candidates from the SDSS and SPY, should provide an updated value for the DWD fraction, as well as observational orbital separation and component-mass distributions, for the first time for the general DWD population (Hallakoun et al, in preparation).…”

“…The Sloan Digital Sk y Surv e y (SDSS; York et al 2000 ) introduced a much larger, though less precise, multi-epoch spectroscopic sample of a few tens of thousands WDs, that has so far led to the disco v ery of a few DWDs and DWD candidates (e.g. Badenes et al 2009 ;Mullally et al 2009 ;Breedt et al 2017 ;Chandra et al 2021 ). Due to its lower resolution, the SDSS sample is sensitive only to DWDs with orbital separations ࣠ 0.05 au.…”

The Eighteenth Data Release of the Sloan Digital Sky Surveys: Targeting and First Spectra from SDSS-V

“…Gaia has recently produced enormous, well-defined samples of WDs (∼250,000 objects). SDSS-V is enlarging the subset of these WDs that have complementary spectroscopy (especially in the southern hemisphere) and also providing multi-epoch observations for empirical input on the binary WD merging channels toward type Ia supernovae and other remnant products (e.g., Chandra et al 2021).…”

A Systematic Search for Short-period Close White Dwarf Binary Candidates Based on Gaia EDR3 Catalog and Zwicky Transient Facility Data

“…The known classical VBs catalog includes 11 AM CVn-type binaries, 13 detached DWDs, and 1 hot subdwarf binary (Kupfer et al 2018). Up until now, a total of ∼87 candidate VBs have all been found in the electromagnetic band (Burdge et al 2019a(Burdge et al , 2020a(Burdge et al , 2020bHuang et al 2020;Chandra et al 2021;Kilic et al 2021;Brown et al 2022). In addition, there are other potential GW sources such as helium-star binaries, short-period CVs, exoplanets, brown dwarfs, and substellar companies (Amaro- .…”